Oscillating-current system



Nov. 24, 1925. v 1,562,569

C. V. LOGWOOD OSCILLATING CURRENT SYSTEM Fi1ed May 28, 1921 ..1 J0 .JM

fs w f E l J0 43 L /f V INVENTOR ma ,00 20o BYQ: ATTORNEYS@ mr @aT/ Patented Nov. 24, i925..

UNITED `f? CHRIJE V. LOGWOOD, Oli' 'NEW YRK, Ill. Y.

OSGILLATING-CRRENT SYSTEM.

Application med may es,

'useful Invention in @Scillating-Current Systems, of which 'the following is a specilieation. y y

This invention relates to oscillating current systems, and is especially adapted for use in connection with radio frequencyoscillations systems such as' are used in radio: communications for .the transmission and reception'of signals.

The object of the invention is to provide a system which is simple in structure, eflicient in o eration, and wherein the power obtained rom alternating current generators, particularly of the vacuum tube type, may be l.greatly increased.

Further objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, combination, location and relative arrangement of circuits and electrical in'strumentalities employed in connection therewith and .the method utilized, all as will bemore fully hereinafter set forth as shown by the accompanying drawing and finally pointed out in the appended claims.

Referring to the drawing,-

Fig. 1 is a diagrammatic View of the wiring diagram embodying the principles of my invention g Fig. 2 is an enlarged detail diagrammatic view showing the type of transformer employed in accordance with my invention;

Fig. 3 is a diagrammatic view of the characteristic curve of the thermionic type of oscillator or generator.

The same part is designated by the same reference character wherever it occurs throughout the several views.

lVhile I have shown and will now describe my invention as particularly applied to a radio transmitting station, whereby the principles of my invention may be readily understood, I wish it to be borne in mind that I do not desire t be limited or restricted to this particular application of my invention, as the same may be utilized in various other uses such as for reception of a radio signals as an amplifier or for a relay for alternating currents irrespective of whether or not they be of audio or radio frequency. The-essence of the invention is that by suita- 1921. serial no. 473,363.

Vble:circuit--arrangeinents amplification of an enormous extent is obtained, and it will he apparent to those skilled in the art that while, as above stated, I have selected amplification of oscillating current energy at a Vtransmitting station to illustrate the principles of my invention, its applicability to other use will be at once seen.

Referring to the drawing, 1 designates the antenna which is connected to earth through the usual induetance through the primary condenser 4, and, if desired, the 'ammeter 5. One terminal of the inductance 3 is adjustably connected to the plate electrede 6 of audiony The grid electrode 8 of audion 7 is connected through eondensers 9 and 10 to the grid electrode llfof audion 12. The grid electrodes 8 and 11 are like- -wise connected vtogether through choke coils 13 and secondary winding 14 of a modulation transformer. The primary coil 15 of the modulation transformer is included in the circuit preferably containing an inductance coil 16, a source of current 17, and the signal switch 18. Or, if desired, it may be included in the circuitcontaining current source 19,-and a microphone 20, all depending upon whether it is desired to utilize the transmitting system for telegraph or telephone. The filament electrodes 21 of the audions 7 and 11, are in this instance connected in parallel, `and are lighted `from a suitable current source 22, controlled by an adjustable rheostat 23.' From the approximate center of the secondary coil 14- of the modulationv transformer I connect a high resista-nce element 25. 26 designates the usual B battery which-'in `this instance is shown as a direct current machine. The current passes from the positive terminal of the direct current machineto the middle of 'the two coils of the transformerv generallydesignated 27, and through the coil 28 thereminal of the generator 26. is through the coil 31 of transformer 37, choke coil 32, to the plate electrode 6, of audion 7 The two windings 28 and 31 are so wound that the fields thereof are opposed to each other as long as-the current is owing freely in both coils 28 and 31. It will, therefore, be ob- Viens that if the circuit was oscillatin that both ofthe plate electrodes of the au ions 7 and 12 would deliver their energy at the same rat-e and at the same frequency because the grid electrodes 8 and 11 would be changing their potential at the same time andat the same frequency, and this wouldY be true even if the plate electrode 6 of audion 7 were the only one that is in an oscillating circuit.

If, for a given instant, the impulse from the modulation transformer 15,14, is positive, it would put a positive charge on the grid electrode' 8 of audion 7. This would cause a slight increase of current through the plate electrode 6 thereof at the same time the negative impulse 'was impressed on the grid electrode llof audion 12. rlhis .wouldcause a big drop in the current of the to the voltage building up in the windings 43 and" 44, the condenser 45 becomes charged. By means of this arrangement it will be apparent that the negative impulse caused by the induced current in the winding 44 to add to the plate electrode 6, thereby serves to add still further to the slighty increase of the plate current as when the grid 8 of audion 7 was charged positive. It will be apparent that the result is an addition to the radiation which is secured, and it will further be apparent that a discharge A of the condenser 45 further increases this addition. The next reversal of the impulses p in the modulation makes the radiation dropv because this time the grid velectrode 11 of audion 12 is made positive, and the slight increase of the plate current will not make as much change of potential as the negative charge 6 When the negative charge on the grid 8 of audion 7 causes a big drop of current through the audion 7, this tends to build up a potential on the plate electrode 30'of audion'12, by a sudden change of current through the plate 6 of audion 7, which induces currents in the windings of the transformer" 27 as hereinbefore described.`

The building up of current in the audion 12 does not affect the radiation, as willbe apparent, because the audion tube 7 is the only tube ein loyed- 'which is in the 0scillating circuit. The function of the resistance leak 2 5 is to allow the collecting negative charge on the grid electrodes 8 and 11 to leak ed to the filament. The

characteristic curve of the modern power.

tubeas illustrated in Fig. 3 shows that the plate current grid voltage when plotted has a steep rise in the plate current on the negative half of the cycle to one half of the saturation current. The curve then flattens out until the positive half of the cycle is A far beyond on the positive half, so that the change vof potential of the modulation transformer has little effect upon the characteristic current.

lVhile I have described what at the present time appearsto me to be the theoretical explanation of the operation of the system of my invention, I do not advance the same as beingtlie ,only explanation which can be advanced, and I therefore, desire to have the foregoing discussion of the theory of operation regarded as an effort to advance one theory of operation which will permit the circuit employed to be understood.

s liereinbefore mentioned, the transformer 27 requires as its essential elements the opposed windings 28, 81 and 43, 44,and while I have 'shown an especially constructed transformer, and will new proceed to describe the same in detail, I do not desire to be limited or restricted to such special construction.

- The core of the transformer illustrated at 50 is preferably made of laminated pieces, and may or may not be a solid closed netic circuit. In practice I prefer to employ1 an air gap as illustrated, or at least an'open coie. I also prefer to employ one to one ratio. Each of the transformer coils has about two thousand turnsjof insulated` wire arranged, in layers, each layer insulated` from its adjacent layer, for example, by oil paper, so as to protect the windings from the high potentials which surge in the.A coils. The size of the wire employed depends upon thev current load. It will be apparent thatthe function of the transformer is to react in such a way that whenever one of the tubes 7, 12, in the circuit is robbed of its current, the induced currents in the other windings assist the currents of the other tubes.

Referriner again to Fig. 1, the impedance coil 52 and the condenser 53 employed in the circuit, including the current source 2G. are used for smoothing off the ripples in the circuit in which a coinmutator is located.

Many modifications and changes in detail will readily occur to those skilled in the art without departing from the spirit and scope of my invention. Therefore, having shown and described a structure embodying the principles of my invention, and having set forth the objects and nature thereof, what l claimas new and useful and of my own nvention and desire to secure by Leiters Patent is: l A

1. An I4oscillation generator system comprising two audions havingthe plate eloctrodes thereof connected in parallel, an oscillating circuit operatively associated with the plate electrodes of said audions, a circuit inclui'lingl a source of current connecting said plate electrodes and tlieilameut lill) trodes of said audions, the coils of said transformer being arranged in pairs with the windings thereof opposed to each other substantially as and for the purpose described. v

l1. The combination with two associated audions and their circuits, the plate electrodes of said audions being connected in parallel, of circuits connecting said plate electrodes to the filament electrodes of said audions', including a source of current, and means whereby a decrease in the space current between the plate and filament electrodes of one audion causes a corresponding increase of the space current between the plate and filament electrodes of the other audion, and an oscillatory circuit4 operatively associated with the plate electrodes of said audions. e

l2. The combination with two associated audions and their circuits, the plate electrodes of said audions being connected in parallel, of a circuit connecting said plate electrodes to the filament electrodes of said audions, including a source of current, and

means included in said circuit whereby a decrease in the space current between the plate and filament electrodes of one audion causes a corresponding increase of the space current between the plate and filament electrodes of the other audion, and an oscillating circuit operatively associated with the plate electrodes of said audions.

In testimony whereof I have hereunto set my hand on this 24 day of May, A. D., 1921.

CHARLES V. LOGWOOD. 

